The present invention relates to improved lifting gear comprising a stationary or mobile chassis, a variable height mast comprising a base section connected to said chassis and at least one movable section that can move with respect to said base section between a lowered position in which said at least one movable section is collapsed, and a raised position in which said at least one movable section is deployed upward, a lifting platform connected to said mast via the movable section that is intended to be the highest deployed section, by means of at least one articulated arm.
This type of lifting gear is widely used in trade and industry for working heights and, more particularly, for working over obstacles, especially in warehouses in order to access the top shelves; or in workshops and other areas of industrial; or commercial activity. The mast can be deployed upward in order to raise the platform or gondola containing at least one operator or a load, and the articulated arm allows the platform or gondola to be moved away from the mast to give the operator or the load access over an obstacle.
Lifting gear of this existing type works perfectly well, but in some cases is too bulky in the lengthwise direction when in the lowered position. This drawback restricts or complicates the use of such gear which in particular cannot get into lifts or goods lifts, or cannot be maneuvered down narrow trafficways or in cluttered areas that are encountered in workshops, warehouses, commercial areas, or the like.
The present invention sets out to overcome this drawback.
One object of the present invention is, therefore, to offer lifting gear of reduced length which at the same time allows an excellent radius of action for the lifting platform.
Another object of the present invention is also to offer a device with a lower total weight.
Another object of the present invention is to offer a device of lower total cost and excellent reliability.
More specifically, the invention consists in improved lifting gear comprising:
a stationary or mobile chassis,
a variable-height mast comprising a base section connected to said chassis and at least one movable section that can move with respect to said base section between a lowered position in which said at least one movable section is collapsed, and a raised position in which said at least one movable section is deployed upward,
a lifting platform connected to said mast via the movable section that is intended to be the highest deployed section, by means of at least one articulated arm,
characterized in that said at least one articulated arm is connected to said movable section intended to be the highest deployed section and positioned with respect to the latter laterally so that said at least one articulated arm is outside of a space between said lifting platform and said mast in the lowered position.
The lateral connection and the lateral position of the articulated arm makes it possible to free up all of the space between the lifting platform and the mast so that the platform can abut the mast or be very close to the latter in the lowered position, leading to the greatest possible reduction in the collapsed length of the lifting gear.
The prior art teaches the use of an articulated arm placed between the gondola or the lifting platform and the mast. A design of this kind, guided by an idea of symmetry, of obviousness, and of balancing of forces, does, however, increase the length of the lifting gear or of the lifting platform by the thickness of the arm and sometimes of the ram that actuates this arm; any solution using this design which allows the bulk of these elements to be reduced not, however, allowing their thickness to be canceled out completely.
According to an advantageous feature of the present invention, said lifting platform is connected to said at least one articulated arm laterally in such a way that it can be placed, in said lowered position, symmetrically with respect to the longitudinal axis of said lifting gear.
According to an additional advantageous feature, the lifting gear according to the invention comprises at least one ram for actuating said at least one articulated arm, and said at least one ram is arranged between said mast and said articulated arm.
According to another advantageous feature, said articulated arm comprises a parallelogram structure and said ram acts more or less along a diagonal of said parallelogram.
According to another advantageous feature, said mast comprises at least two successive sections, which are juxtaposed and joined together so that they can slide by means of slideways.
According to an advantageous feature which is in addition to the previous feature, said sections are joined together in such a way that said lifting platform is connected to the section which is furthest away from it when said mast is in the lowered position.
According to an alternative feature, said mast comprises at least two successive sections with tubular profiles, nesting one inside the other in sliding fashion.
Other features and advantages will become clear from reading the description which follows of several embodiments of lifting gear according to the invention, accompanied by the appended drawings, the embodiments being given by way of illustration and without implying any restriction on the way in which the invention can be interpreted.